Time it takes to design creatively. Ease of use. Quality of final product. And I do this for a living so it's worth the investment and time learning how to use it.
I also don't actually want any of the the albums from the sites that offer free but clunky software. I don't ever want second best if I can help it, and I just don't love any albums I've found in the UK.
Loxley is OK, but the smell and finish reminded me of when I was shopping for a new Sofa. It's a perfectly good album though but just doesn't quite seem 'special'. Folio was a little more to my taste but still lacking a certain 'something'. Obviously much of it comes down to taste though.
Queensberry are another company I often here people claim are 'the best', but I don't see it personally although I can't argue they don't have a very high quality finish. I just find it doesn't matter how good the finish is, if the product lacks soul.
I ordered a sample album using smartalbums and it should be here in the next few days. The guy's over in Turkey tell me they are very happy with how it's turned out, so hopefully I'm just as happy with it. Tbh I really can't fault their service so far, they let me even send them custom fonts so the album matches the look/branding of my blog.